Patent Document 1 discloses a technique of displaying an image of a selected display region (corresponding to an “emphasized display region” in the present specification) in an emphasized state.
In addition, Patent Document 2 discloses a technique of changing an operation mode to a luminance decrease, a reduced display, a display stop, and a power supply stop in this order when a state in which no person is present continues for a certain period or more.    Patent Document 1: Japanese Patent Laid-open No. Hei 8-320679    Patent Document 2: Japanese Patent Laid-Open No. 2000-242255